2023, October 25: Arcturus Double Take, Bright Moon, Planets

Venus, Jupiter, Mars, Regulus, October 25, 2015
Photo Caption – Venus, Jupiter, Mars, Regulus, October 25, 2015


by Jeffrey L. Hunt

Chicago, Illinois:  Sunrise, 7:14 a.m. CDT; Sunset, 5:55 p.m. CDT.  Check local sources for sunrise and sunset times. Times are calculated by the US Naval Observatory’s MICA computer program.

Summaries of Current Sky Events
Summary for Venus as a Morning Star, 2023-24

Here is today’s planet forecast:

Morning Sky

Chart Caption – 2023, October 25: Arcturus is visible in the eastern sky before daybreak.

The bright star Arcturus is making its first morning appearance in the east-northeast before sunrise.  The star is nearly 30 light years away, shining with an intensity of 100 suns.  It is the second brightest star, after Sirius, that is visible from the mid-northern latitudes and the brightest in the northern half of the sky.

Arcturus shines in the western sky after sunset as well.  Find it this evening over 10° above the west-northwest horizon about an hour after sunset.

The star is far enough north that it can appear in the western sky after sunset and in the eastern sky before sunrise.  At this season, it is below the horizon over three hours less than the sun.  This results in Arcturus appearing in the western evening sky and rising into the eastern sky before sunrise.

The Big Dipper is used to identify the star.  The curved dipper’s handle points toward Arcturus.  During the mornings at this season, the pattern is standing on its handle in the northeastern sky.  On the accompanying chart, Alkaid is at the end of the handle.  Look for Arcturus during morning twilight in the eastern sky and again in the western sky during evening twilight.

Chart Caption – 2023, October 25: Brilliant Venus is in the east-southeast with Leo during morning twilight.

Brilliant Venus stands about 30° up in the east-southeast to the upper right of Arcturus at an hour before daybreak.  Venus appears in front of Leo’s stars, over 15° to the lower left of Regulus, the Lion’s brightest star, and nearly 14° to the right of Denebola, the tail.  The planet’s movement against the starfield is easy to note from one morning to the next. It passes Denebola in a wide conjunction November 1st.

Chart Caption – Venus clouds from the Hubble Space Telescope. The planet shows phases. (NASA photo)

Venus shows phases through a telescope.  This morning 51% of the planet is illuminated from our view, a slight gibbous phase.  Two mornings ago, Venus reached greatest elongation, the farthest the planet appears from the sun from our view.  The phase continues to grow and the planet’s size diminishes through a telescope as Venus recedes into the distance.  

Chart Caption – 2023, October 25: Jupiter is in the western sky about one hour before sunrise.

Bright Jupiter is in the western sky at this hour, nearly 125° from Venus.  As Venus steps eastward and Jupiter slowly retrogrades, moves westward against the starfield, the gap opens.  When it reaches 180° on December 10th, Jupiter sets as the queen of the morning sky rises.  After that date, Jupiter sets until Venus rises for nearly the remainder of this Venusian apparition.  The two planets have a very close conjunction on May 23, 2024, but they are lost in the sun’s glare.

This morning the Jovian Giant is over 20° above the western horizon. It passes between Menkar, part of Cetus, and Hamal, Aries’ brightest star, in three mornings.

Evening Sky

Photo Caption – Mercury as Never Seen Before. (NASA photo)

Mercury and Mars are immersed in bright sunlight and they are not visible this evening.  Mercury reaches greatest elongation December 4, but in the northern hemisphere its visibility suffers from a poorly inclined solar system plane.

Mars is heading toward its solar conjunction, November 18th, and a slow reappearance in the morning sky during the new year.

Chart Caption – 2023, October 25: Saturn and the moon are in the southeastern sky after sundown.

The bright gibbous moon, 88% illuminated, is in the east-southeast after sundown.  The planet Saturn, nearly 30° up in the south-southeast, is over 20° to the upper right of the lunar orb, and about 20° above the star Fomalhaut.

This evening, Neptune is in the same binocular field with the bright moon, 2.6° to the upper left of the lunar orb.  The planet is quite dim, and even on moonless nights, it is a challenging view.  Sky watchers with telescopes can see it easier.  Strangely, the magnification of the telescope somewhat dims the bright moonlight.

Chart Caption – 2023, October 25: Two hours after sundown, Jupiter is in the eastern sky.

The moon is about one-third of the way from Saturn to Jupiter.  At one hour after sundown, Jupiter is less than 10° up in the east-northeast.  An hour later it is nearly 20° up in the east. The moon is near Jupiter in three evenings.


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